EMI Filter Basics
Welcome to the knowledge world of EMI Filters
As the process of modern society continues to accelerate, electronic equipment has gradually covered the entire industry, such as living facilities, medical industry, military and aerospace fields. Electronic devices becomes more and more important increasingly.
What makes the EMI Filters emerged, in order to prevent damage to those various electronic equipment.
So what exactly was the damage caused and why it happened?
However, the electromagnetic interference they generate interferes with each other, causing equipment malfunction or even collapse.
EMI filters can effectively block unnecessary interference and get stable current input. Here we take EMI as the basis and carefully study the role of EMI filters and their impact on various fields.
What is electromagnetic interference?
Electromagnetic interference (EMI) is the interference caused by one electrical or electronic device to another electrical or electronic device due to the electromagnetic field generated by its operation
When EMI occurs, it will affect the normal use of equipment and increase the chance of accidents. Due to the different degrees of EMI impact, it generally leads to weakening of signal quality, failure of equipment components and even equipment damage.
What is electromagnetic compatibility?
EMC (Electromagnetic Compatibility) is a term that is often used when we discuss EMI. Electromagnetic compatibility (EMC) means that a device or system operates in compliance with the requirements in its electromagnetic environment and does not cause intolerance to any equipment in its environment.
The ability of electromagnetic interference. Therefore, EMC includes two requirements: on the one hand, it means that the electromagnetic interference caused by the equipment to the environment during normal operation cannot exceed a certain limit; on the other hand, it means that the electromagnetic interference existing in the environment of the equipment has a certain limit. Degree of immunity, i.e. electromagnetic susceptibility
In the United States, the Federal Communications Commission regulates EMI under Title 47 Part 15, which addresses noise immunity and noise emissions from equipment in various industries. Internationally, the International Special Committee on Radio Interference regulates conducted and radiated EMI in the industrial, commercial, residential and automotive sectors. EMC is also regulated by various European standards, including EN55011 for industrial equipment and EN55022 for IT equipment.
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Classification of EMI
Classified according to production method:
1. Naturally occurring EMI:
This type of EMI can come from many sources - lightning strikes, solar flares, cosmic noise, atmospheric electrical storms, solar magnetic storms, dust storms, snowstorms, solar
Naturally occurring electromagnetic interference will occur at any time and will have a serious impact on unprotected electronic and electrical equipment. For example, solar flares and solar magnetic storms may affect military equipment or satellite transmission signals. Snowstorms in a smaller area may cause Radio static electricity and interference with mobile phone signals in certain areas.
2. Man-made EMI:
residential, industrial. This type of EMI usually comes from other electronic circuits, although some EMI can be caused by switching of large currents, etc.
Electromagnetic interference (EMI) in residential buildings:
The electromagnetic interference generated in the house mainly comes from wireless signal operating equipment. Although this electromagnetic interference will not cause particularly serious damage, it will still cause poor performance and weak signals of other electronic equipment in the house.
Common EMI sources in residences: mobile phones, computers, microwave ovens, refrigerators, washing machines, heaters, Bluetooth devices, etc.
With the development and use of more and more household electronic devices, the impact of residential electromagnetic interference sources continues to grow. As more and more people use electronic devices such as mobile phones and computers, the density of electromagnetic currents in the environment is getting higher and higher. As people continue to use more and more devices and in closer proximity, these devices are more likely to cause and fall victim to electromagnetic interference.
Improvements in the performance of electronic devices have also increased the electromagnetic interference they can cause. As electronics are subject to increasingly stringent performance expectations, these devices operate at higher frequencies and produce electromagnetic noise over a wider range of frequencies than in the past. EMI filters designed to block electromagnetic noise at specific frequencies may not protect against the higher frequencies produced by newer equipment.
Man-made EMI in industry:
The impact of EMI in industry is usually a mixture of large-scale and diverse EMI, which can cause serious interference to critical facilities and equipment. EMI is one of the most pressing issues in industrial applications. It can damage systems, equipment and electronics used in critical applications such as medical, military, aerospace, public transportation systems, navigation, vehicle control systems and industrial touch screens.
Common industrial EMI sources: electric motors and generators, cellular networks and telephone transmissions, television transmissions, radio and satellites, grid power supplies, railway and public transportation systems, medical equipment, other high-frequency EMI sources
In the industrial sector, EMI can affect equipment in various industries and lead to downtime, data loss, or permanent damage to equipment. In the military and medical fields, the impact of EMI on mission-critical functions can be even more severe.
Classification according to mode of communication
1. Conducted EMI: Conducted EMI spreads through conductors (such as wires or power lines)
Conducted emission is what the name suggests when there is a conductive path through which a signal can travel. This can be along power cables or other interconnecting cables. Conduction can be in one of two modes:
Common Mode: This type of EMI coupling occurs when noise on two conductors appears in the same phase, such as output and return signals, or +ve and -ve for a power line.
Differential Mode: This occurs when the noise on the two conductors is out of phase.
The required filtering techniques will vary depending on the type of EMI coupling experienced. For common mode lines, filter them together. For differential mode, they can be filtered together.
2. Radiated EMI: Radiated EMI spreads through the air and does not require a conductor
This type of EMI coupling can be significant. It is a type of EMI coupling that is typically experienced when the source and victim are separated by a large distance (usually more than a wavelength). The source radiates a signal that may or may not be desired, and the victim receives the signal in a way that destroys its performance.
Sort by duration:
1. Continuous interference: This type of EMI usually comes from sources such as circuits that emit continuous signals. However, continuous background noise can be generated in a variety of ways, whether man-made or naturally occurring.
2. Occasional interference is also called impulse noise: Similarly, this type of EMI may be man-made or naturally occurring. Lightning, ESD, and switching systems all generate impulse noise, which is a form of EMI.
Dangers of EMI
From residences to industrial facilities, EMI can cause hazards of varying sizes and bring about a series of problems. In mild cases, EMI can have an annoying impact on the performance quality of the life-generating equipment we use, such as: Poor mobile phone signal, Bluetooth signal reception, computer failure, damage to large household appliances, etc.
In more serious cases, EMI may cause inestimable losses, such as communication interruption, medical equipment failure, television broadcast signal interruption, military equipment failure, etc. The impact of EMI depends on the duration of the interference, the interference environment and the anti-interference ability of the equipment.
What is an EMI filter?
EMI filter is a passive electronic component, which is composed of capacitor, inductor and resistive components. EMI filter is also called EMI suppression filter. It is a very effective anti-electromagnetic interference electronic component.
What are the functions of EMI FILTER?
The main function of the EMI filter is to reduce the impact of electromagnetic interference.
It can eliminate high-frequency noise on power lines, prevent magnetic field interference caused by ground loops, and further reduce the external electromagnetic interference and self-generated electromagnetic radiation of the power supply system.
When connected to equipment or circuits, EMI filters can suppress transmission through conduction electromagnetic noise. These filters screen out any unwanted current conducted through wires or cables while allowing the desired current to flow freely. EMI filters that suppress grid power supply noise are also called EMI power line filters.
How EMI FILTER work?
EMI filter (Electromagnetic Interference Filter) is an electronic device used to suppress electromagnetic interference. Its working principle is based on two main mechanisms: series and parallel.
First, the series mechanism is used to suppress electromagnetic interference propagated by power lines by placing the filter on the power line of the equipment to be protected. The filter usually contains one or more inductive components inside, which have a high impedance to high-frequency noise, thereby absorbing or blocking these noise signals. In addition, the filter can also contain capacitive elements to attenuate high-frequency signals.
Second, the parallel mechanism is used to suppress electromagnetic interference propagated by the signal lines by placing the filter between the signal pins of the line. The filter usually contains one or more capacitive components to form a low-pass filter to block the propagation of high-frequency noise signals.
Through the function of series and parallel connection, EMI filters can effectively suppress the propagation of electromagnetic interference signals, thereby protecting the normal operation of the equipment to be protected. It is worth noting that the specific design and working principle of EMI filters may vary depending on different applications and needs.
Application of EMI FILTER
Different EMI filters can be applied in different ways to most effectively prevent damage caused by electromagnetic noise. EMI filters are widely used in various electronic equipment, communication equipment and circuits to suppress electromagnetic interference and ensure the normal operation and stable performance of the equipment. The following are some common EMI filter applications:
Appliances and Washing Machines: White goods EMI filters suppress electromagnetic noise from a variety of household appliances, from washing machines to treadmills. These filters ensure that devices meet electromagnetic compatibility regulations and help protect them from EMI damage that can affect their performance.
Single Phase: DOREXS Single-phase EMI filters are very effective for small equipment such as home appliances and electronics, as well as industrial applications such as food service equipment, power supplies, and telecommunications.DOREXS Single-phase EMI filters are also compatible with fitness equipment and motor controls. Such as model DAA1, DAA2, DBA3, DBA4, DBA7
Three-Phase: For tighter EMI suppression, DOREXS three-phase EMI filters block higher levels of noise with a three-stage filtering system. Three-phase EMI filters are suitable for high-power applications such as industrial machinery and motors, medical equipment, test equipment, and industrial tools. Such as DAC1, DAC3, DAC4
Military: Military EMI filters are designed to meet regulatory and compliance standards for EMC of military equipment. These reliable EMI filters protect aerospace and military communications systems from damage, allowing for safe operation. EMI filters designed specifically for HEMP protection can also be used to protect against EMI threats.
Medical Grade EMI Filters: Medical grade EMI filters meet the current requirements of medical applications and protect sensitive medical equipment from damage. Effective and reliable EMI filters for medical applications can save lives and prevent electromagnetic noise interference.
DOREXS is the expert in the EMI industry
If you need effective EMI protection or EMC testing, DOREXS can provide reliable and durable EMI filters for every application. Our EMI filters include high-quality EMI filters for professional applications in the military, aerospace and medical fields, as well as cost-effective EMI filters for small household equipment and industrial uses. If you need an EMI filter with special custom requirements, our team of experts can design an EMI suppression filter that meets your specific requirements.
With 15 years of EMI experience, DOREXS is a trusted manufacturer of high-quality EMI filters for medical, military, commercial and residential applications. All our EMI filters are designed to comply with industry standards and comply with EMC regulations. Explore our selection of EMI filters or submit a custom quote request to get the perfect EMI filter for your needs. For more information about DOREXS custom and standard EMI filters, please contact us.